htexpr compiles an html-like template syntax into Python
expressions, allowing embedded Python expressions in attributes and
content. It is inspired by JSX and intended to complement the
excellent Dash package, which allows you to write single-page
React apps in Python. For motivation and further instructions, see the
documentation.
A Unicode table:
import dash
from dash import dcc, html, Input, Output, State
from htexpr import compile
import unicodedata
app = dash.Dash()
app.layout = compile("""
<div>
<table style={"margin": "0 auto"}>
<tr><th>char</th><th>name</th><th>category</th></tr>
[
(<tr style={'background-color': '#eee' if line % 2 else '#ccc'}>
<td>{ char }</td>
<td>{ unicodedata.name(char, '???') }</td>
<td>{ unicodedata.category(char) }</td>
</tr>)
for line, char in enumerate(chr(i) for i in range(32, 128))
]
</table>
</div>
""").run()
app.run_server(debug=True)Further demonstrations:
- a larger Unicode table
- a Bootstrap example
I wrote this to help me with a particular project where I kept making bracketing mistakes. The code works for that project, but there are likely to be corner cases I haven't considered.
The Python grammar used here is quite simplistic: it recognizes strings and variously parenthesized expressions. By understanding more Python it would probably be possible to disambiguate between comparison operators and tags, and thus drop the requirement to enclose nested expressions in parentheses.
The error messages are not always helpful, and in particular the code objects don't yet have reliable line-number data.